/*

Copyright 1986, 1998  The Open Group

Permission to use, copy, modify, distribute, and sell this software and its
documentation for any purpose is hereby granted without fee, provided that
the above copyright notice appear in all copies and that both that
copyright notice and this permission notice appear in supporting
documentation.

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
OPEN GROUP BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Except as contained in this notice, the name of The Open Group shall not be
used in advertising or otherwise to promote the sale, use or other dealings
in this Software without prior written authorization from The Open Group.

*/

#ifdef HAVE_CONFIG_H
# include "config.h"
#endif

#include <X11/Xlib.h>
#include <X11/Xos.h>
#include <X11/Xatom.h>
#include <stdio.h>
#include <ctype.h>
#include <stdint.h>

#ifdef X_POSIX_C_SOURCE
#define _POSIX_C_SOURCE X_POSIX_C_SOURCE
#include <signal.h>
#undef _POSIX_C_SOURCE
#else
#if defined(X_NOT_POSIX) || defined(_POSIX_SOURCE)
#include <signal.h>
#else
#define _POSIX_SOURCE
#include <signal.h>
#undef _POSIX_SOURCE
#endif
#endif

#include <sys/wait.h>
#include <errno.h>
#include <setjmp.h>
#include <stdarg.h>

#ifdef __APPLE__
#include <AvailabilityMacros.h>
#if __MAC_OS_X_VERSION_MIN_REQUIRED >= 1060
#include <vproc.h>
#endif
#endif

#if !defined(SIGCHLD) && defined(SIGCLD)
#define SIGCHLD SIGCLD
#endif

#include <stdlib.h>
extern char **environ;
char **newenviron = NULL;
char **newenvironlast = NULL;

#ifndef SHELL
#define SHELL "sh"
#endif

#ifndef HAVE_WORKING_VFORK
# ifndef vfork
#  define vfork() fork()
# endif
#else
# ifdef HAVE_VFORK_H
#  include <vfork.h>
# endif
#endif

/* A/UX setpgid incorrectly removes the controlling terminal.
   Per Posix, only setsid should do that. */
#ifdef macII
#define setpgid setpgrp
#endif


#ifdef HAS_EXECVPE
#define Execvpe(path, argv, envp) execvpe(path, argv, envp)
#else
#define Execvpe(path, argv, envp) execvp(path, argv)
#endif

const char * const server_names[] = {
#ifdef ibm				/* IBM */
    "Xibm        IBM AED, APA, 8514a, megapel, VGA displays on PC/RT",
#endif
#ifdef macII				/* MacII */
    "XmacII      Apple monochrome display on Macintosh II",
#endif
#ifdef XFREE86
    "XFree86     XFree86 displays",
#endif
#ifdef XORG
    "Xorg        Common X server for most displays",
#endif
#ifdef __APPLE__
    "Xquartz     Mac OSX Quartz displays.",
#endif
    "Xvfb        Virtual frame buffer",
    "Xfake       kdrive-based virtual frame buffer",
    "Xnest       X server nested in a window on another X server",
    "Xephyr      kdrive-based nested X server",
    NULL};

#ifndef XINITRC
#define XINITRC ".xinitrc"
#endif
char xinitrcbuf[256];

#ifndef XSERVERRC
#define XSERVERRC ".xserverrc"
#endif
char xserverrcbuf[256];

#define	TRUE		1
#define	FALSE		0
#define	OK_EXIT		0
#define	ERR_EXIT	1

static char *default_server = "X";
static char *default_display = ":0";		/* choose most efficient */
static char *default_client[] = {"xterm", "-geometry", "+1+1", "-n", "login", NULL};
static char *serverargv[100];
static char *clientargv[100];
static char **server = serverargv + 2;		/* make sure room for sh .xserverrc args */
static char **client = clientargv + 2;		/* make sure room for sh .xinitrc args */
static char *displayNum = NULL;
static char *program = NULL;
static Display *xd = NULL;			/* server connection */
#if defined(__CYGWIN__) || defined(SVR4) || defined(_POSIX_SOURCE) || defined(CSRG_BASED) || defined(__UNIXOS2__) || defined(Lynx) || defined(__APPLE__)
int status;
#else
union wait	status;
#endif
int serverpid = -1;
int clientpid = -1;
volatile int gotSignal = 0;

static void Execute ( char **vec, char **envp );
static Bool waitforserver ( void );
static Bool processTimeout ( int timeout, char *string );
static int startServer ( char *server[] );
static int startClient ( char *client[] );
static int ignorexio ( Display *dpy );
static void shutdown ( void );
static void set_environment ( void );
static void Fatal(char *msg);
static void Error ( char *fmt, ... );

static int 
sigCatch(int sig)
{
	/* On system with POSIX signals, just interrupt the system call */
	gotSignal = sig;
}

static int 
sigAlarm(int sig)
{
#if defined(SYSV) || defined(SVR4) || defined(linux) || defined(__UNIXOS2__) || defined(__APPLE__)
	signal (sig, sigAlarm);
#endif
}

static int
sigUsr1(int sig)
{
#if defined(SYSV) || defined(SVR4) || defined(linux) || defined(__UNIXOS2__) || defined(__APPLE__)
	signal (sig, sigUsr1);
#endif
}

static void 
Execute(char **vec,		/* has room from up above */
	char **envp)
{
    Execvpe (vec[0], vec, envp);
    if (access (vec[0], R_OK) == 0) {
	vec--;				/* back it up to stuff shell in */
	vec[0] = SHELL;
	Execvpe (vec[0], vec, envp);
    }
    return;
}

int
main(int argc, char *argv[])
{
	register char **sptr = server;
	register char **cptr = client;
	register char **ptr;
	int pid;
	int client_given = 0, server_given = 0;
	int client_args_given = 0, server_args_given = 0;
	int start_of_client_args, start_of_server_args;
	struct sigaction sa;
#ifdef __APPLE__
#if __MAC_OS_X_VERSION_MIN_REQUIRED >= 1060
	vproc_transaction_t vt;
#endif
#endif

	program = *argv++;
	argc--;
	/*
	 * copy the client args.
	 */
	if (argc == 0 ||
	    (**argv != '/' && **argv != '.')) {
		for (ptr = default_client; *ptr; )
			*cptr++ = *ptr++;
	} else {
		client_given = 1;
	}
	start_of_client_args = (cptr - client);
	while (argc && strcmp(*argv, "--")) {
		client_args_given++;
		*cptr++ = *argv++;
		argc--;
	}
	*cptr = NULL;
	if (argc) {
		argv++;
		argc--;
	}

	/*
	 * Copy the server args.
	 */
	if (argc == 0 ||
	    (**argv != '/' && **argv != '.')) {
		*sptr++ = default_server;
	} else {
		server_given = 1;
		*sptr++ = *argv++;
		argc--;
	}
	if (argc > 0 && (argv[0][0] == ':' && isdigit(argv[0][1])))
		displayNum = *argv;
	else
		displayNum = *sptr++ = default_display;

	start_of_server_args = (sptr - server);
	while (--argc >= 0) {
		server_args_given++;
		*sptr++ = *argv++;
	}
	*sptr = NULL;

	/*
	 * if no client arguments given, check for a startup file and copy
	 * that into the argument list
	 */
	if (!client_given) {
	    char *cp;
	    Bool required = False;

	    xinitrcbuf[0] = '\0';
	    if ((cp = getenv ("XINITRC")) != NULL) {
		(void) snprintf (xinitrcbuf, sizeof(xinitrcbuf), "%s", cp);
		required = True;
	    } else if ((cp = getenv ("HOME")) != NULL) {
		(void) snprintf (xinitrcbuf, sizeof(xinitrcbuf),
				 "%s/%s", cp, XINITRC);
	    }
	    if (xinitrcbuf[0]) {
		if (access (xinitrcbuf, F_OK) == 0) {
		    client += start_of_client_args - 1;
		    client[0] = xinitrcbuf;
		} else if (required) {
		    fprintf (stderr,
			     "%s:  warning, no client init file \"%s\"\n",
			     program, xinitrcbuf);
		}
	    }
	}

	/*
	 * if no server arguments given, check for a startup file and copy
	 * that into the argument list
	 */
	if (!server_given) {
	    char *cp;
	    Bool required = False;

	    xserverrcbuf[0] = '\0';
	    if ((cp = getenv ("XSERVERRC")) != NULL) {
		(void) snprintf (xserverrcbuf, sizeof(xserverrcbuf), "%s", cp);
		required = True;
	    } else if ((cp = getenv ("HOME")) != NULL) {
		(void) snprintf (xserverrcbuf, sizeof(xserverrcbuf),
				 "%s/%s", cp, XSERVERRC);
	    }
	    if (xserverrcbuf[0]) {
		if (access (xserverrcbuf, F_OK) == 0) {
		    server += start_of_server_args - 1;
		    server[0] = xserverrcbuf;
		} else if (required) {
		    fprintf (stderr,
			     "%s:  warning, no server init file \"%s\"\n",
			     program, xserverrcbuf);
		}
	    }
	}

	/*
	 * put the display name into the environment
	 */
	set_environment ();

	/*
	 * Start the server and client.
	 */
#ifdef SIGCHLD
	signal(SIGCHLD, SIG_DFL);	/* Insurance */
#endif

	/* Let those signal interrupt the wait() call in the main loop */
	memset(&sa, 0, sizeof sa);
	sa.sa_handler = sigCatch;
	sigemptyset(&sa.sa_mask);
	sa.sa_flags = 0;	/* do not set SA_RESTART */
	
	sigaction(SIGTERM, &sa, NULL);
	sigaction(SIGQUIT, &sa, NULL);
	sigaction(SIGINT, &sa, NULL);
	sigaction(SIGHUP, &sa, NULL);
	sigaction(SIGPIPE, &sa, NULL);

	signal(SIGALRM, sigAlarm);
	signal(SIGUSR1, sigUsr1);

#ifdef __APPLE__
#if __MAC_OS_X_VERSION_MIN_REQUIRED >= 1060
	vt = vproc_transaction_begin(NULL);
#endif
#endif

	if (startServer(server) > 0
	 && startClient(client) > 0) {
		pid = -1;
		while (pid != clientpid && pid != serverpid
		       && gotSignal == 0
			)
			pid = wait(NULL);
	}

#ifdef __APPLE__
#if __MAC_OS_X_VERSION_MIN_REQUIRED >= 1060
	vproc_transaction_end(NULL, vt);
#endif
#endif

	signal(SIGTERM, SIG_IGN);
	signal(SIGQUIT, SIG_IGN);
	signal(SIGINT, SIG_IGN);
	signal(SIGHUP, SIG_IGN);
	signal(SIGPIPE, SIG_IGN);

	shutdown();

	if (gotSignal != 0) {
		Error("unexpected signal %d.\n", gotSignal);
		exit(ERR_EXIT);
	}

	if (serverpid < 0 )
		Fatal("Server error.\n");
	if (clientpid < 0)
		Fatal("Client error.\n");
	exit(OK_EXIT);
}


/*
 *	waitforserver - wait for X server to start up
 */
static Bool
waitforserver(void)
{
	int	ncycles	 = 120;		/* # of cycles to wait */
	int	cycles;			/* Wait cycle count */

#ifdef __APPLE__
	/* For Apple, we don't get signaled by the server when it's ready, so we just
	 * want to sleep now since we're going to sleep later anyways and this allows us
	 * to avoid the awkard, "why is there an error message in the log" questions
	 * from users.
         */

	sleep(2);
#endif

	for (cycles = 0; cycles < ncycles; cycles++) {
		if ((xd = XOpenDisplay(displayNum))) {
			return(TRUE);
		}
		else {
		    if (!processTimeout (1, "X server to begin accepting connections")) 
		      break;
		}
	}

	fprintf (stderr, "giving up.\r\n");
	return(FALSE);
}

/*
 * return TRUE if we timeout waiting for pid to exit, FALSE otherwise.
 */
static Bool
processTimeout(int timeout, char *string)
{
	int	i = 0, pidfound = -1;
	static char	*laststring;

	for (;;) {
#if defined(SVR4) || defined(_POSIX_SOURCE) || defined(Lynx) || defined(__APPLE__)
		if ((pidfound = waitpid(serverpid, &status, WNOHANG)) == serverpid)
			break;
#else
		if ((pidfound = wait3(&status, WNOHANG, NULL)) == serverpid)
			break;
#endif
		if (timeout) {
			if (i == 0 && string != laststring)
				fprintf(stderr, "\r\nwaiting for %s ", string);
			else
				fprintf(stderr, ".");
			fflush(stderr);
		}
		if (timeout)
			sleep (1);
		if (++i > timeout)
			break;
	}
	if ( i > 0 ) fputc( '\n', stderr );     /* tidy up after message */
	laststring = string;
	return( serverpid != pidfound );
}

static int
startServer(char *server[])
{
	sigset_t mask, old;

	sigemptyset(&mask);
	sigaddset(&mask, SIGUSR1);
	sigprocmask(SIG_BLOCK, &mask, &old);

	serverpid = fork(); 

	switch(serverpid) {
	case 0:
		/* Unblock */
		sigprocmask(SIG_SETMASK, &old, NULL);

		/*
		 * don't hang on read/write to control tty
		 */
#ifdef SIGTTIN
		(void) signal(SIGTTIN, SIG_IGN);
#endif
#ifdef SIGTTOU
		(void) signal(SIGTTOU, SIG_IGN);
#endif
		/*
		 * ignore SIGUSR1 in child.  The server
		 * will notice this and send SIGUSR1 back
		 * at xinit when ready to accept connections
		 */
		(void) signal(SIGUSR1, SIG_IGN);
		/*
		 * prevent server from getting sighup from vhangup()
		 * if client is xterm -L
		 */
		setpgid(0,getpid());
		Execute (server, environ);
		Error ("no server \"%s\" in PATH\n", server[0]);
		{
		    const char * const *cpp;

		    fprintf (stderr,
"\nUse the -- option, or make sure that \"%s\" is a program or" \
"a link to the right type of server\n",
		             server[0]);
		    fprintf (stderr,
"for your display.  Possible server names include:\n\n");
		    for (cpp = server_names; *cpp; cpp++) {
			fprintf (stderr, "    %s\n", *cpp);
		    }
		    fprintf (stderr, "\n");
		}
		exit (ERR_EXIT);

		break;
	case -1:
		break;
	default:
		/*
		 * don't nice server
		 */
#ifdef PRIO_PROCESS
		setpriority( PRIO_PROCESS, serverpid, -1 );
#endif

		errno = 0;
		if (! processTimeout(0, "")) {
			serverpid = -1;
			break;
		}
		/*
		 * kludge to avoid race with TCP, giving server time to
		 * set his socket options before we try to open it,
		 * either use the 15 second timeout, or await SIGUSR1.
		 *
		 * If your machine is substantially slower than 15 seconds,
		 * you can easily adjust this value.
		 */
		alarm (15);

		sigsuspend(&old);
		alarm (0);
		sigprocmask(SIG_SETMASK, &old, NULL);

		if (waitforserver() == 0) {
			Error("unable to connect to X server\r\n");
			shutdown();
			serverpid = -1;
		}
		break;
	}

	return(serverpid);
}

static void
setWindowPath(void)
{
	/* setting WINDOWPATH for clients */
	Atom prop;
	Atom actualtype;
	int actualformat;
	unsigned long nitems;
	unsigned long bytes_after;
	unsigned char *buf;
	const char *windowpath;
	char *newwindowpath;
	unsigned long num;
	char nums[10];
	int numn;
	size_t len;
	prop = XInternAtom(xd, "XFree86_VT", False);
	if (prop == None) {
#ifdef DEBUG
		fprintf(stderr, "no XFree86_VT atom\n");
#endif
		return;
	}
	if (XGetWindowProperty(xd, DefaultRootWindow(xd), prop, 0, 1, 
		False, AnyPropertyType, &actualtype, &actualformat, 
		&nitems, &bytes_after, &buf)) {
#ifdef DEBUG
		fprintf(stderr, "no XFree86_VT property\n");
#endif
		return;
	}
	if (nitems != 1) {
#ifdef DEBUG
		fprintf(stderr, "%lu items in XFree86_VT property!\n", nitems);
#endif
		XFree(buf);
		return;
	}
	switch (actualtype) {
	case XA_CARDINAL:
	case XA_INTEGER:
	case XA_WINDOW:
		switch (actualformat) {
		case  8:
			num = (*(uint8_t  *)(void *)buf);
			break;
		case 16:
			num = (*(uint16_t *)(void *)buf);
			break;
		case 32:
			num = (*(uint32_t *)(void *)buf);
			break;
		default:
#ifdef DEBUG
			fprintf(stderr, "format %d in XFree86_VT property!\n", actualformat);
#endif
			XFree(buf);
			return;
		}
		break;
	default:
#ifdef DEBUG	    
		fprintf(stderr, "type %lx in XFree86_VT property!\n", actualtype);
#endif
		XFree(buf);
		return;
	}
	XFree(buf);
	windowpath = getenv("WINDOWPATH");
	numn = snprintf(nums, sizeof(nums), "%lu", num);
	if (!windowpath) {
		len = 10 + 1 + numn + 1;
		newwindowpath = malloc(len);
		if (newwindowpath == NULL) 
		    return;
		snprintf(newwindowpath, len, "WINDOWPATH=%s", nums);
	} else {
		len = 10 + 1 + strlen(windowpath) + 1 + numn + 1;
		newwindowpath = malloc(len);
		if (newwindowpath == NULL)
		    return;
		snprintf(newwindowpath, len, "WINDOWPATH=%s:%s", 
			 windowpath, nums);
	}
	*newenvironlast++ = newwindowpath;
	*newenvironlast = NULL;
}

static int
startClient(char *client[])
{
	setWindowPath();
	if ((clientpid = vfork()) == 0) {
		if (setuid(getuid()) == -1) {
			Error("cannot change uid: %s\n", strerror(errno));
			_exit(ERR_EXIT);
		}
		setpgid(0, getpid());
		environ = newenviron;
		Execute (client,newenviron);
		Error ("no program named \"%s\" in PATH\r\n", client[0]);
		fprintf (stderr,
"\nSpecify a program on the command line.\r\n\n");
		_exit (ERR_EXIT);
	}
	return (clientpid);
}

#ifndef HAVE_KILLPG
#define killpg(pgrp, sig) kill(-(pgrp), sig)
#endif

static jmp_buf close_env;

static int 
ignorexio(Display *dpy)
{
    fprintf (stderr, "%s:  connection to X server lost.\r\n", program);
    longjmp (close_env, 1);
    /*NOTREACHED*/
    return 0;
}

static void 
shutdown(void)
{
	/* have kept display opened, so close it now */
	if (clientpid > 0) {
		XSetIOErrorHandler (ignorexio);
		if (! setjmp(close_env)) {
		    XCloseDisplay(xd);
		}

		/* HUP all local clients to allow them to clean up */
		errno = 0;
		if ((killpg(clientpid, SIGHUP) != 0) &&
		    (errno != ESRCH))
			Error("can't send HUP to process group %d\r\n",
				clientpid);
	}

	if (serverpid < 0)
		return;
	errno = 0;
	if (killpg(serverpid, SIGTERM) < 0) {
		if (errno == EPERM)
			Fatal("Can't kill X server\r\n");
		if (errno == ESRCH)
			return;
	}
	if (! processTimeout(10, "X server to shut down")) {
	    fprintf (stderr, "\r\n");
	    return;
	}

	fprintf(stderr, 
	"\r\n%s:  X server slow to shut down, sending KILL signal.\r\n",
		program);
	fflush(stderr);
	errno = 0;
	if (killpg(serverpid, SIGKILL) < 0) {
		if (errno == ESRCH)
			return;
	}
	if (processTimeout(3, "server to die")) {
		fprintf (stderr, "\r\n");
		Fatal("Can't kill server\r\n");
	}
	fprintf (stderr, "\r\n");
	return;
}


/*
 * make a new copy of environment that has room for DISPLAY
 */

static void 
set_environment(void)
{
    int nenvvars;
    char **newPtr, **oldPtr;
    static char displaybuf[512];

    /* count number of environment variables */
    for (oldPtr = environ; *oldPtr; oldPtr++) ;

    nenvvars = (oldPtr - environ);
    newenviron = (char **) malloc ((nenvvars + 3) * sizeof(char **));
    if (!newenviron) {
	fprintf (stderr,
		 "%s:  unable to allocate %d pointers for environment\n",
		 program, nenvvars + 3);
	exit (1);
    }

    /* put DISPLAY=displayname as first element */
    snprintf (displaybuf, sizeof(displaybuf), "DISPLAY=%s", displayNum);
    newPtr = newenviron;
    *newPtr++ = displaybuf;

    /* copy pointers to other variables */
    for (oldPtr = environ; *oldPtr; oldPtr++) {
	if (strncmp (*oldPtr, "DISPLAY=", 8) != 0
	 && strncmp (*oldPtr, "WINDOWPATH=", 11) != 0) {
	    *newPtr++ = *oldPtr;
	}
    }
    *newPtr = NULL;
    newenvironlast=newPtr;
    return;
}

static void
Fatal(char *msg)
{
	Error(msg);
	exit(ERR_EXIT);
}

static void
Error(char *fmt, ...)
{
        va_list ap;

	va_start(ap, fmt);
	fprintf(stderr, "%s:  ", program);
	if (errno > 0)
	  fprintf (stderr, "%s (errno %d):  ", strerror(errno), errno);
	vfprintf(stderr, fmt, ap);
	va_end(ap);
}
